1. Field of the Invention
The present invention relates to an image-output inspection system, an image inspection apparatus, and a computer program product.
2. Description of the Related Art
In most of large-scale printer systems and printing press systems, a printer controller for generating a printer image is installed in a different housing from that of a print output device or a printer and placed at a position away from the print output device or printer. With regard to a format of image data transmitted from the printer controller to the print output device, there are two methods, one method transmits CMYK multi-valued bitmap data (for example, 8-bit data) and another method transmits CMYK bitmap data subjected to halftone processing (for example, 2-bit data). A data amount of CMYK bitmap data subjected to halftone processing is smaller than a data amount of CMYK multi-valued bitmap data, and hence, transfer processing load is reduced by using the method transmitting CMYK bitmap data subjected to halftone processing.
Meanwhile, there is a known inspection apparatus that inspects a print state of a print output medium and determines whether the print state of the medium is good or not. In general, such an inspection apparatus is added to an image forming apparatus as an optional extra, to form a part of an image-output inspection system. Conventional inspection apparatuses for inspecting a print job improve accuracy of inspection by, for example, treating multi-valued CMYK bitmap data subjected to raster image processing (RIP), in Which bitmap expansion is performed on the basis of a printer language, as a correct image data, as in a technology disclosed in Japanese Patent No. 3836107.
However, when the bitmap data subjected to halftone processing is employed to facilitate a transfer process as described above, an inspection apparatus added as an optional extra can use only bitmap data of a small amount subjected to halftone processing even though it is preferable to use multi-valued data which is not subjected to halftone processing.
Namely, CMYK 2-bit data subjected to halftone processing is data subjected to dithering, and it is difficult to accurately compare the position of each halftone dot of correct image data for inspection with the position of each halftone dot of data read by an image reader. Consequently, using CMYK 2-bit data subjected to halftone processing as correct image data for inspection makes it difficult for the inspection apparatus to perform an accurate inspection.